Precursor supply unit, substrate processing system, and method of fabricating semiconductor device using the same

ABSTRACT

Provided are a precursor supply unit, a substrate processing system, and a method of fabricating a semiconductor device using the same. The precursor supply unit may include an outer container, an inner container provided in the outer container and used to store a precursor source, a gas injection line having an injection port, which is provided below the inner container and in the outer container and is used to provide a carrier gas into the outer container, and a gas exhaust line having an exhaust port, which is provided below the inner container and in the outer container and is used to exhaust the carrier gas in the outer container and a precursor produced from the precursor source.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a divisional of U.S. application Ser. No. 16/030,323 filed onJul. 9, 2018, which claims priority under 35 U.S.C. § 119 to KoreanPatent Application No. 10-2017-0104749, filed on Aug. 18, 2017, in theKorean Intellectual Property Office, the contents of which are herebyincorporated by reference in its entirety.

FIELD

The present disclosure relates to a system for and a method offabricating a semiconductor device, and in particular, to a precursorsupply unit, a substrate processing system, and a method of fabricatinga semiconductor device using the same.

BACKGROUND

Generally, a process of fabricating a semiconductor device includes aprocess of depositing a thin film using, for example, a chemical vapordeposition (CVD) method or an atomic layer deposition (ALD) method. Aprecursor source in a liquid or solid state is used in the thin filmdeposition process. The liquid or solid precursor source is vaporized orsublimated to form a vaporized or gaseous precursor. The precursor isdelivered into a chamber by a carrier gas. In a general precursor supplyunit, a source consumption space on the precursor source may be the sameas the precursor passage space. If the precursor source is consumed, asupply pressure of the precursor may be reduced. If the supply pressureis reduced, a deposition rate of a thin film is reduced.

SUMMARY

Some embodiments of the inventive concept provide a precursor supplyunit and/or a processing system, which are configured to prevent orsuppress a reduction in the supply pressure of a precursor in a gasphase, which may occur when a liquid or solid precursor source isconsumed.

Some embodiments of the inventive concept provide a method of preventinga deposition rate from being decreased and a method of fabricating asemiconductor device using the same.

According to some embodiments of the inventive concept, a precursorsupply unit may include an outer container, an inner container providedin the outer container and used to store a precursor source, a gasinjection line having an injection port, which is provided below theinner container and in the outer container and is used to provide acarrier gas into the outer container, and a gas exhaust line having anexhaust port, which is provided below the inner container and in theouter container and is used to exhaust the carrier gas in the outercontainer and a precursor produced from the precursor source. The innercontainer may include a supporting membrane supporting the precursorsource. The supporting membrane may have pores that are permeable to thecarrier gas and the precursor. The supporting membrane provides aprecursor passage space defined by a first internal space between aninner bottom of the outer container and a bottom surface of thesupporting membrane.

According to some embodiments of the inventive concept, a substrateprocessing system may include a chamber including a susceptor, which isconfigured to receive a substrate, a precursor supply unit supplying aprecursor onto the substrate, and a carrier gas supply unit supplying acarrier gas, which is used to deliver the precursor in the chamber, intothe precursor supplying unit. The precursor supply unit may include anouter container, an inner container provided in the outer container andused to store a precursor source, a gas injection line having aninjection port, which is provided below the inner container and in theouter container and is used to provide a carrier gas into the outercontainer, and a gas exhaust line having an exhaust port, which isprovided below the inner container and in the outer container and isused to provide the carrier gas in the outer container and theprecursor. The inner container may include a supporting membranesupporting the precursor source. The supporting membrane may have poresthat are permeable to the carrier gas and the precursor. The supportingmembrane provides a precursor passage space defined by a first internalspace between an inner bottom of the outer container and a bottomsurface of the supporting membrane.

According to some embodiments of the inventive concept, a method offabricating a semiconductor device may include providing a precursor anda carrier gas on a substrate in a chamber and providing a reaction gas,which can be reacted with the precursor, on the substrate to form a thinfilm on the substrate. Providing the precursor and the carrier gas mayinclude supplying a carrier gas into a precursor passage space between asupporting membrane of an inner container and an inner bottom surface ofan outer container, the inner container containing a precursor source,providing the carrier gas to the precursor source on the supportingmembrane through pores of the supporting membrane, and obtaining theprecursor through the pores using the carrier gas, without a reductionin supply pressures of the carrier gas and the precursor according toconsumption of the precursor source in the inner container.

According to some embodiments of the inventive concept, the sourceconsumption space and the gas pathway space may be separated from eachother, and thus, it may be possible to prevent the supply pressure ofthe precursor gas and the carrier gas from being reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

Example embodiments will be more clearly understood from the followingbrief description taken in conjunction with the accompanying drawings.The accompanying drawings represent non-limiting, example embodiments asdescribed herein.

FIG. 1 is a diagram illustrating a substrate processing system accordingto some embodiments of the inventive concept.

FIGS. 2A and 2B are sectional views illustrating an example of theprecursor supplying unit of FIG. 1.

FIG. 3 is a sectional view illustrating an example of the precursorsupplying unit of FIG. 1.

FIG. 4 is a flow chart illustrating a method of fabricating asemiconductor device, according to some embodiments of the inventiveconcept.

FIG. 5 is a flow chart illustrating an example of the step of providinga precursor and a carrier gas, shown in FIG. 4.

It should be noted that these figures are intended to illustrate thegeneral characteristics of methods, structure and/or materials utilizedin certain example embodiments and to supplement the written descriptionprovided below. These drawings are not, however, to scale and may notprecisely reflect the structural or performance characteristics of anygiven embodiment, and should not be interpreted as defining or limitingthe range of values or properties encompassed by example embodiments.For example, the relative thicknesses and positioning of molecules,layers, regions and/or structural elements may be reduced or exaggeratedfor clarity. The use of similar or identical reference numbers in thevarious drawings is intended to indicate the presence of a similar oridentical element or feature.

DETAILED DESCRIPTION

FIG. 1 illustrates a substrate processing system 100 according to someembodiments of the inventive concept.

Referring to FIG. 1, the substrate processing system 100 may be achemical vapor deposition (CVD) system or an atomic layer deposition(ALD) system. Alternatively, the substrate processing system 100 may bea substrate etching system. In some embodiments, the substrateprocessing system 100 may include a chamber 10, a precursor supplyingunit 20, a carrier gas supplying unit 30, a reaction gas supplying unit40, first to third gas lines 22, 32, and 42, and first to third valves24, 34, and 44.

The chamber 10 may provide space for isolating a substrate W from theoutside. In some embodiments, the chamber 10 may include a housing 12, asusceptor 14, and a shower head 16. The housing 12 may be provided tosurround the susceptor 14 and the shower head 16. The housing 12 mayinclude a lower housing 11 and an upper housing 13. The susceptor 14 maybe provided in the lower housing 11. If the lower housing 11 isseparated from the upper housing 13, the substrate W may be loaded orunloaded on or from the susceptor 14 by using a robot arm (not shown).The upper housing 13 may be provided on the lower housing 11. The showerhead 16 may be provided in the upper housing. The shower head 16 may beused to supply a precursor 21, a carrier gas 31, and a reaction gas 41onto the substrate W.

The precursor supplying unit 20 may be configured to produce a vaporizedor gaseous precursor 21 from a liquid and/or solid precursor source 50.The precursor source 50 may include at least one of liquidorgano-metallic compounds (e.g., tetrakis(dimethylamido)titanium(TDMAT), or hexacarbonyl(3,3-dimethyl-1-butyne)dicobalt (CCTBA)) orsolid compounds (e.g., hafnium chloride (HfCl4), pentakis-dimethylaminotantalum (PDMAT), or WClx (x=6)), but the inventive concept is notlimited thereto. The vaporized or gaseous precursor 21 may have amolecule size smaller than that of the precursor source 50.

The carrier gas supplying unit 30 may be used to provide the carrier gas31 into the precursor supplying unit 20. The carrier gas 31 may includean inactive or inert gas (e.g., argon gas or helium gas). The carriergas 31 may be used to carry and/or deliver the precursor 21 in theprecursor supplying unit 20 into the chamber 10.

The reaction gas supplying unit 40 may be configured to supply thereaction gas 41 into the chamber 10. The reaction gas 41 may be reactedwith the precursor 21 on the substrate W to form a thin film depositedon the substrate W. The reaction gas 41 may include hydrogen (H₂) gas orammonia (NH₃) gas.

The first gas line 22 may be configured to connect the precursorsupplying unit 20 to the chamber 10. The precursor 21 and the carriergas 31 may be supplied into the chamber 10 through the first gas line22. The second gas line 32 may be configured to connect the carrier gassupplying unit 30 to the precursor supplying unit 20. The carrier gas 31may be supplied into the precursor supplying unit 20 through the secondgas line 32. The third gas line 42 may be configured to connect thereaction gas supplying unit 40 to the chamber 10. The reaction gas 41may be supplied into the chamber 10 through the third gas line 42.

The first to third valves 24, 34, and 44 may be coupled to the first tothird gas lines 22, 32, and 42, respectively. The first valve 24 may beprovided between the chamber 10 and the precursor supplying unit 20. Thefirst valve 24 may be used to control supply flow rates of the precursor21 and the carrier gas 31. The second valve 34 may be provided betweenthe precursor supplying unit 20 and the carrier gas supplying unit 30.The second valve 34 may be used to control a supply flow rate of thecarrier gas 31. The third valve 44 may be provided between the reactiongas supplying unit 40 and the chamber 10. The third valve 44 may be usedto control a supply flow rate of the reaction gas 41.

Although not shown, a purge gas supplying unit may be configured tosupply a purge gas (e.g., nitrogen gas (N₂)) into the chamber 10. Aftersupplying the precursor 21 and the carrier gas 31, the purge gas may besupplied into the chamber 10. In addition, after supplying the reactiongas 41, the purge gas may also be supplied into the chamber 10.

A deposition rate of a thin film to be formed on the substrate W may bedetermined by supply pressures and/or supply flow rates of the precursor21 and the carrier gas 31. For example, if the supply pressures of theprecursor 21 and the carrier gas 31 are increased, the deposition rateof the thin film may be increased. By contrast, if the supply pressuresof the precursor 21 and the carrier gas 31 are lowered, the depositionrate of the thin film may be decreased.

In a general precursor source supplying unit, if the remaining amount ofthe precursor source decreases, the supply pressure of the precursor 21may decrease. By contrast, the precursor supplying unit 20 may beconfigured to uniformly control the supply pressure of the precursor 21,regardless of a consumption or remaining amount of the precursor source50. A deposition rate of the thin film may be controlled to be constant,until the precursor source 50 in the precursor supplying unit 20 isexhausted. Hereinafter, the precursor supplying unit 20 will bedescribed in more detail below.

FIGS. 2A and 2B illustrate examples of the precursor supplying unit 20of FIG. 1.

Referring to FIG. 2A, the precursor supplying unit 20 may include acanister. In some embodiments, the precursor supplying unit 20 mayinclude an outer container 210, an inner container 220, a gas injectionline 230, a gas exhaust line 240, and an outer heater 250.

The outer container 210 may be configured to contain the inner container220, the gas injection line 230, and the gas exhaust line 240 therein.The outer container 210 may have a cylindrical shape.

The inner container 220 may be provided in the outer container 210. Theinner container 220 may be used to store the precursor source 50, whichis provided in a liquid or solid state. The inner container 220 may beconfigured to seal the precursor source 50. The inner container 220 maybe a cylindrical structure whose volume is smaller than that of theouter container 210. In some embodiments, the inner container 220 mayinclude a supporting membrane 222 and an upper cover 224.

The supporting membrane 222 may be spaced apart from an inner bottom 212of the outer container 210. The supporting membrane 222 may beconfigured to support the precursor source 50. The supporting membrane222 may be formed of or include porous alumina, porous titania, orporous zirconia. The supporting membrane 222 may have a plurality ofpores 221. The pores 221 may be permeable to the precursor 21 and thecarrier gas 31. For example, the precursor 21 and the carrier gas 31 mayhave a molecular diameter or size of about 1 nm or smaller, and each ofthe pores 221 may have a diameter ranging from about 1 nm to about 1 μm.The pores 221 may not be permeable to the precursor source 50 in theliquid or solid state. The precursor source 50 may be provided orpresent on the pores 221. The carrier gas 31 may be produced from theprecursor source 50, which is in contact with the supporting membrane222, by the precursor 21. The precursor source 50 may be vaporizedand/or sublimated at an interface of the supporting membrane 222.

The precursor 21 may be moved into a space, which is located below thesupporting membrane 222, through the pores 221. Since the precursor 21has a molecular size smaller than that of the precursor source 50, theprecursor 21 may pass through the pores 221. The precursor 21 and thecarrier gas 31 may be positioned in a precursor passage space 202, whichis provided between a bottom surface of the supporting membrane 222 andthe inner bottom 212 of the outer container 210. The precursor passagespace 202 may be defined as an internal space between the bottom surfaceof the supporting membrane 222 and the inner bottom 212 of the outercontainer 210. In addition, a distance between the bottom surface of thesupporting membrane 222 and the inner bottom 212 of the outer container210 may be defined as a height of the precursor passage space 202. Forexample, the height of the precursor passage space 202 may not bechanged, regardless of a consumed or remaining amount of the precursorsource 50.

The upper cover 224 may be provided to cover the precursor source 50 andthe supporting membrane 222. The upper cover 224 may be connected toopposite edge of the supporting membrane 222. The upper cover 224 may beprovided in such a way that a top surface thereof is coplanar with thatof the outer container 210. An edge of the upper cover 224 and an edgeof the supporting membrane 222 may be in contact with or fastened to thegas injection line 230 and the gas exhaust line 240.

The gas injection line 230 may be provided in a side portion of theouter container 210. The gas injection line 230 may extend from thesecond valve 34, which is provided on the outer container 210, towardthe inner bottom 212 of the outer container 210. The gas injection line230 may be interposed between a side surface of the side portion of theouter container 210 and a side surface of a side portion of the innercontainer 220. The gas injection line 230 may be in contact with orfastened to the side surface of the side portion of the outer container210. The gas injection line 230 may have an injection port 232. Theinjection port 232 may be placed in the precursor passage space 202,which is positioned adjacent to the inner bottom 212 of the outercontainer 210. The carrier gas 31 may be provided into the precursorpassage space 202 through the injection port 232. Although not shown,the injection port 232 may be configured to provide the carrier gas 31toward the supporting membrane 222.

The gas exhaust line 240 may be provided in an opposite side portion ofthe outer container 210. The gas exhaust line 240 may extend from thefirst valve 24, which is provided on the outer container 210, toward abottom surface of the supporting membrane 222 of the inner container220. The gas exhaust line 240 may be interposed between a side surfaceof the opposite side portion of the outer container 210 and a sidesurface of an opposite side portion of the inner container 220. The gasexhaust line 240 may be in contact with or fastened to the side surfaceof the opposite side portion of the outer container 210. The gas exhaustline 240 may have an exhaust port 242. The exhaust port 242 may beplaced in the precursor passage space 202, which is positioned adjacentto the supporting membrane 222. The precursor 21 and the carrier gas 31in the precursor passage space 202 may be exhausted to the gas exhaustline 240 through the exhaust port 242. The precursor 21 and the carriergas 31 in the gas exhaust line 240 may be provided into the chamber 10.

The outer heater 250 may be placed on an outer circumference surface ofthe outer container 210. The outer heater 250 may be used to heat theouter container 210. A creation amount of the precursor 21 may beincreased in proportion to the temperature of the precursor source 50.The outer heater 250 may be used to heat the outer container 210 to atemperature that is lower than a vaporization or sublimation temperatureof the precursor source 50.

Referring to FIG. 2B, as a cumulative supply amount of the precursor 21increases, an amount of the precursor source 50 remaining in the innercontainer 220 may be reduced. If the precursor source 50 is consumed, asource consumption space 204 may be formed in the upper cover 224. Thesource consumption space 204 may be an internal space defined between atop surface of the precursor source 50 and an inner top surface of theupper cover 224. As the remaining amount of the precursor source 50 isreduced, the source consumption space 204 may be enlarged or expanded.

In some embodiments, the supporting membrane 222 and the precursorsource 50 may separate the precursor passage space 202 from the sourceconsumption space 204. A size of the source consumption space 204 may beinversely proportional to the remaining amount of the precursor source50. If the remaining amount of the precursor source 50 is reduced, thesize of the source consumption space 204 may be increased. By contrast,a size of the precursor passage space 202 may be constant regardless ofthe remaining amount of the precursor source 50. Also, supply pressuresof the precursor 21 and the carrier gas 31 in the precursor passagespace 202 may be constant. Accordingly, the supporting membrane 222 mayprevent or suppress a reduction in supply pressures of the precursor 21and the carrier gas 31, which are caused by consumption of the precursorsource 50. It may be possible to prevent a reduction in the depositionrate of a thin film, which may occur when the supply pressures of theprecursor 21 and the carrier gas 31 are reduced. Although not shown, ifall of the precursor source 50 is exhausted, the supporting membrane 222may be positioned at an interface between the precursor passage space202 and the source consumption space 204. Accordingly, the precursorpassage space 202 and the source consumption space 204 may be spacedapart from each other by the supporting membrane 222.

FIG. 3 illustrates another example of the precursor supplying unit 20 ofFIG. 1.

Referring to FIG. 3, the precursor supplying unit 20 may further includeinner heaters 260. The outer container 210, the inner container 220, thegas injection line 230, and the gas exhaust line 240 may be configuredto have substantially the same features as those of FIGS. 2A and 2B.

The inner heaters 260 may be provided on and under the supportingmembrane 222 of the inner container 220. For example, each of the innerheaters 260 may include a grid-shaped heater. The inner heaters 260 maybe configured to heat the supporting membrane 222. The inner heaters 260may be configured to locally heat a portion of the precursor source 50that is located adjacent to the supporting membrane 222. Thevaporization or sublimation of the precursor source 50 at an interfaceof the supporting membrane 222 may be accelerated by the inner heaters260. For example, the inner heaters 260 may be placed on and under thesupporting membrane 222 of the inner container 220. In some embodiments,the inner heaters 260 may include an upper heater 262 and a lower heater264.

The upper heater 262 may be provided on a top surface of the supportingmembrane 222. The upper heater 262 may be placed between the supportingmembrane 222 and the precursor source 50. The upper heater 262 may beused to directly and/or locally heat the precursor source 50 adjacent tothe supporting membrane 222. An amount of the precursor 21 to beproduced may be increased in proportion to a heating temperature of theupper heater 262.

The lower heater 264 may be provided on a bottom surface of thesupporting membrane 222. The lower heater 264 may be used to increaseconvection speed of the carrier gas 31 passing below the supportingmembrane 222. The higher the convection speed of the carrier gas 31, theamount of the precursor 21 to be produced.

The substrate processing system 100 may be used in a process offabricating a semiconductor device, as will be described below.

FIG. 4 is a flow chart illustrating a method of fabricating asemiconductor device, according to some embodiments of the inventiveconcept.

Referring to FIG. 4, a process S100 of fabricating a semiconductordevice may include an ALD method. Alternatively, the fabrication processS100 may include a CVD method or a plasma etching method. In someembodiments, the fabrication process S100 may include supplying thecarrier gas 31 in the precursor supplying unit 20 (in S10), providingthe precursor 21 and the carrier gas 31 on the substrate W (in S20),providing the reaction gas 41 on the substrate W (in S30), and examiningwhether a thickness of a thin film is within a predetermined thicknessrange (in S40). If not, the earlier process steps may be repeated.

The carrier gas supplying unit 30 may provide the carrier gas 31 intothe precursor supplying unit 20 (in S10). The carrier gas 31 may beprovided into the precursor passage space 202.

Next, the precursor supplying unit 20 may be configured to provide thecarrier gas 31 and the precursor 21 onto the substrate W in the chamber10 (in S20). The precursor 21 may be provided into the chamber 10,without a reduction in supply pressure to be caused by consumption ofthe precursor source 50.

FIG. 5 is a flow chart illustrating an example of the step S20 ofsupplying the precursor 21 and the carrier gas 31, shown in FIG. 4.

Referring to FIG. 5, the step S20 of supplying the precursor 21 and thecarrier gas 31 may include providing the carrier gas 31 into theprecursor source 50 through the supporting membrane 222 (in S22),obtaining the precursor 21 from the precursor source 50 using thecarrier gas 31 (in S24), and supplying the carrier gas 31 and theprecursor 21 (in S26).

The precursor supplying unit 20 may be configured to inject the carriergas 31 into the precursor passage space 202 through the gas injectionline 230 and provide the carrier gas 31 to the precursor source 50through the pores 221 (in S22). The precursor source 50 in the liquid orsolid state may be vaporized or sublimated by the carrier gas 31, andthus, the precursor 21 may be produced in the pores 221. If theprecursor source 50 is consumed, a source consumption space 204 may beformed in the upper cover 224 of the inner container 220. If theremaining amount of the precursor source 50 is reduced, a size of thesource consumption space 204 may be increased.

Next, the precursor supplying unit 20 may be configured to obtain theprecursor 21 in the precursor passage space 202, which is located belowthe supporting membrane 222 (in S24). The precursor 21 may beinfiltrated into the precursor passage space 202, which is located belowthe supporting membrane 222. The precursor 21 and the carrier gas 31 maybe mixed with each other in the precursor passage space 202. Since theprecursor passage space 202 has a uniform size, supply pressures of theprecursor 21 and the carrier gas 31 may be constant in the precursorpassage space 202.

Next, the precursor supplying unit 20 may supply the carrier gas 31 andthe precursor 21 to the chamber 10 through the gas exhaust line 240 (inS26). Supply pressures of the precursor 21 and the carrier gas 31 may beconstantly maintained regardless of the consumption of the precursorsource 50. The precursor 21 may be used to form a single precursor layer(not shown) on the substrate W in the chamber 10.

Although not shown, a purge gas may be provided into the chamber 10. Thepurge gas may be used to remove the precursor 21 from the chamber 10.

Referring back to FIG. 4, the reaction gas supplying unit 40 may supplythe reaction gas 41 onto the substrate W (in S30). The reaction gas 41may be reacted with the precursor 21 on the substrate W, thereby forminga thin film deposited on the substrate W. The thin film may include asingle layer and/or an atomic layer whose thickness ranges from aboutseveral angstroms to about several nanometers.

Although not shown, a purge gas may be provided into the chamber 10. Thepurge gas may be used to remove the reaction gas 41 from the chamber 10.

Next, a controller (not shown) may examine whether a thickness of thethin film is within a predetermined thickness range (in S40). If thethickness of the thin film is not within the predetermined thicknessrange, the steps S10 to S40 may be repeated.

According to some embodiments of the inventive concept, in a precursorsupply unit, a source consumption space, in which a liquid or solidprecursor source is consumed, is separated from a precursor passagespace, and this may make it possible to suppress or prevent a reductionin supply pressure of the precursor in the precursor passage space,which is caused by consumption of the precursor source. In addition, itmay be possible to prevent a reduction in deposition rate of a thinfilm, which may be caused by the reduction of the supply pressure.

While example embodiments of the inventive concepts have beenparticularly shown and described, it will be understood by one ofordinary skill in the art that variations in form and detail may be madetherein without departing from the spirit and scope of the attachedclaims.

What is claimed is:
 1. A method of fabricating a semiconductor device,comprising: providing a precursor and a carrier gas on a substrate in achamber; and providing a reaction gas, which is reacted with theprecursor, on the substrate to form a thin film on the substrate throughreaction with the precursor, wherein the providing the precursor and thecarrier gas comprises: supplying the carrier gas into a precursorpassage space between a supporting membrane of an inner container and aninner bottom surface of an outer container, the inner containercontaining a precursor source; providing the carrier gas to theprecursor source on the supporting membrane through pores of thesupporting membrane; and obtaining the precursor through the pores usingthe carrier gas, without a reduction in supply pressures of the carriergas and the precursor according to consumption of the precursor sourcein the inner container.
 2. The method of claim 1, wherein the pores ofthe supporting membrane allow the carrier gas and the precursor to passtherethrough, and the supporting membrane supports the precursor sourceto separate a source consumption space on the precursor source from theprecursor passage space.
 3. The method of claim 2, wherein theproviding, the precursor and the carrier gas further comprisesexhausting the precursor and the carrier gas in the precursor passagespace to supply the precursor and the carrier gas into the chamber. 4.The method of claim 1, further comprising providing a purge gas in thechamber, after the providing the precursor or after the providing thereaction gas.
 5. The method of claim 1, wherein forming the thin filmcomprises depositing an atomic layer.